HDMI (High-Definition Multimedia Interface) is a compact audio/video interface for transmitting digital data between equipment, such as between a satellite television receiver or a Digital Video Disc (DVD) player and a television monitor. Previous interconnection technologies, such as radio-frequency (RF) coaxial cable, composite video, S-video, etc., relied on analog transmission. HDMI provides a high quality digital alternative.
HDMI cables have become increasingly prevalent in consumer applications. This increased deployment coincides with a general increase in complexity associated with household audio and video systems. One problem that has been noted with HDMI cables in particular is a susceptibility to poor or incomplete connections, since the HDMI connectors of standard configuration have a tendency to come loose from movement or vibration of the audio/video equipment. This problem can be quite costly. For instance, cable television operators frequently deploy technicians to consumers' homes to resolve loss-of-picture complaints that turn out to be loose connections at an HDMI port.
U.S. Pat. No. 8,257,299 to Ray (hereinafter “the Ray patent”), which is incorporated by reference herein in its entirety, describes an HDMI plug assembly that is designed to form a secure connection with a corresponding female HDMI receptacle. The HDMI plug assembly described in the Ray patent includes a slot-shaped opening in the wall of the connector body (i.e., the male HDMI plug section that interfaces with the corresponding female HDMI receptacle). A movable tooth extends outward from the slot-shaped opening. The tooth engages with a leading edge of the female HDMI receptacle when the connector body is fully inserted into the female HDMI receptacle. The engaged tooth provides a secure connection that resists low-level pull out forces applied to the HDMI cable. When a sufficient pull out force is applied to the movable tab, the movable tab retreats downward so as to release the plug from the leading edge of the female HDMI receptacle. The features of the tooth can be controlled such that the movable tab remains engaged with the leading edge of the female HDMI receptacle at low-level forces that correspond to unintentional pulling on the HDMU cable, but releases at a higher level force threshold (e.g., 8.8 lbs.), which protects the mating HDMI receptacle and components connected thereto from damage.
There is a strong desire in the industry to minimize and simplify the plug portion of HDMI cables. By reducing the volumetric footprint of the plug and cable portions, an HDMI connection can be effectuated in much smaller spaces and induce much lower loads on the ever shrinking new equipment. For instance, in the case of a wall-mounted television, a smaller-sized pug portion coupled with a less rigid cable/plug interface will dramatically improve the clearance between the television and wall. A smaller footprint can also beneficially reduce component cost. However, miniaturizing and simplifying HDMI plugs with retention features, such as the HDMI plug assembly described in the Ray patent, presents numerous design challenges, as the smaller footprint makes it difficult to provide a movable tab that will function properly and will maintain adequate retention over repeated plug-in/plug-out cycles.